Pressure-Tailored Self-Driven and Broadband Photoresponse in PbI₂

Photoelectric devices based on the photothermoelectric (PTE) effect show promising prospects for broadband detection without an external power supply. However, effective strategies are still required to regulate the conversion efficiency of light to heat and electricity. Herein, significantly enhanced photoresponse properties of PbI₂ generated from a PTE mechanism via a high-pressure strategy are reported. PbI₂ exhibits a stable, fast, self-driven, and broadband photoresponse at ≈980 nm. Intriguingly, the synergy of the photoconductivity and PTE mechanism is conducive to enhancing the photoelectric properties, and extending the detection bandwidth to the optical communication waveband (1650 nm) with an external bias. The dramatically enhanced photoresponse characteristics are attributed to narrowing of the band gap and a significantly decreased resistance, which originate from the enhancement of atomic orbital overlap owing to pressure-induced Pb-I bond contraction. These findings open up a new avenue toward designing self-driven and broadband photoelectric devices.